Timing Dual Carbs, 27 deg vs 35 deg vs ??? Options

[jr91472]

I am sorry if this has been covered already, but my search revealed nothing.

I am wondering about the timing for carbs on 1.7 / 2.0 motors. I have read that some use 27 other use 35. What kind of difference should I expect and which is the correct setting for different applications.

For me, I have a 1.7 with and an unknown (carb friendly) cam.

thanks
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[SLITS]

Using 35 or there abouts may provide for a "peppier" engine, but it will also heat up the heads faster and they will run at a higher temperature which may lead to a dropped valve seat.

I've lost three engines and they were timed at 34, but I cannot place the blame solely on "overadvance" as "overrev" came into play. All were FI too.

[Aaron Cox]

i use 28 with my mallory dizzy....

[DBCooper]

General rule is to advance it till it pings and then back off a few degrees. If you can't hear the pings (loud exhaust or old ears, for example) then you'll generally be safe at 30 degrees. Some engines want more advance, some less, so that's a real general rule of thumb.

Ron's absolutely right, too much advance will make it run hot, and if your carbs are running lean at the same time it will kill it pretty quick. So keep an eye on the cylinder head temperatures and plug colors until you find the right timing for your engine.

[jr91472]

Thanks boys!

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[last337]

Just a question on this. When setting timing for carbs should it be set at 3500 rpm?

[euro911]

Depends on the advance curve in the dizzy you're running, compression ratio, fuel type, blah, blah, blah ...

Someone posted a good list of dizzy specs for different displacement engines (Bowlsby?). Then you can have a speed shop with a distributor test machine check it out.

[last337]

Depends on the advance curve in the dizzy you're running, compression ratio, fuel type, blah, blah, blah ...

Someone posted a good list of dizzy specs for different displacement engines (Bowlsby?). Then you can have a speed shop with a distributor test machine check it out.

I am using an old 009 dizzy. I am not able to find that list you are talking about. I set it last night to about 27 degrees at 3000rpm and it seemed to run really well. I guess a plug test will tell

[SLITS]

Depending upon which 009 you are using, the advance curve may be to short for the Type 4 engine, so your initial advance is high.

The popular 009 used in VWs was used on static engines that ran at a constant speed (powering water pumps, generators, etc).

But if yours runs good, ignore what I said.

[peteyd]

i had my engine on the dyno 3 weeks ago and we were playing around with the timing. 27 degrees gave me the highest hp reading.

[euro911]

Still looking for the list I was thinking about, but found another chart in a timing tech article on the Bird Board Click here

[last337]

How can I tell which dizzy I have? I don't see any markings on it anywhere?

[SLITS]

If it is a Bosch ... it will have a number stamped into the case like 0 231 178 009. Even the Brazilian Bosch had it. The 009 was strictly mechanical advance and did not have a vacuum pot attached to it.

At this point, I wouldn't worry to much about it. If you want to read, there are a bunch of threads on this board that define the 009 as better used in a float test in a lake.

I have no dog in this hunt and have never used one when I had 4 cyl engines.

[last337]

Haha okay then having said that, what would be a good dizzy for me to get given my current setup? I have a 2.0 with what I think is stock cam and dual weber 40s

[VaccaRabite]

If you can't hear the pings (loud exhaust or old ears, for example) then you'll generally be safe at 30 degrees.

Could be dangerous advice.

I'd not go above 28 degrees unless you know what pinging sounds like and are able to hear it, or have gauges on the car to tell you where to tune to.

It depends heavily on the engine. On my car, 30 was pinging.

Zach

[last337]

If you can't hear the pings (loud exhaust or old ears, for example) then you'll generally be safe at 30 degrees.

Could be dangerous advice.

I'd not go above 28 degrees unless you know what pinging sounds like and are able to hear it, or have gauges on the car to tell you where to tune to.

It depends heavily on the engine. On my car, 30 was pinging.

Zach

Just to clarify, you mean 28 measured at 3000rpm or idle?

[VaccaRabite]

If you can't hear the pings (loud exhaust or old ears, for example) then you'll generally be safe at 30 degrees.

Could be dangerous advice.

I'd not go above 28 degrees unless you know what pinging sounds like and are able to hear it, or have gauges on the car to tell you where to tune to.

It depends heavily on the engine. On my car, 30 was pinging.

Zach

Just to clarify, you mean 28 measured at 3000rpm or idle?

3000.

[last337]

I was just rereading the timing procedure and I'm wondering if im even doin it right. I have an adjustable timing light and I just set it to 27 and revved warm engine to 3k and turned distributor until painted mark lined up with notch. However, I am wondering if the painted mark indicates tdc (0 degrees) or if it was put there to indicate 27 degrees in which case I should set light to zero and rotate distributor until it lines up with notch. How can I tell what painted mark indicates easiest?

[euro911]

Found it Click here

If it's a stock 2.0L FI engine, it should be either a 039 905 205 or 039 905 205A depending on the year of the car (actually year of engine and FI system). The 009 shouldn't be used on a Type-4 engine.

[Elliot Cannon]

I was just rereading the timing procedure and I'm wondering if im even doin it right. I have an adjustable timing light and I just set it to 27 and revved warm engine to 3k and turned distributor until painted mark lined up with notch. However, I am wondering if the painted mark indicates tdc (0 degrees) or if it was put there to indicate 27 degrees in which case I should set light to zero and rotate distributor until it lines up with notch. How can I tell what painted mark indicates easiest?

There is a mark on mine at 0 tdc and another one for 27. There is another mark. You have to get under the car and look through the hole where the trans mates to the engine (I think). When you can see that mark, look at the indicator on the top of the fan and whatever mark is showing at that time is 0 tdc. The mark not far from it is 27. Clear as mudd??